Merc 2018 60 hp CT - slight whine at approx 1800 RPMs

[Canufixit2]

Hi,
Two year old MErc, bought new, well serviced, Merc 2018 60 hp CT on an18 foot Pontoon.. I recently noticed a slight whine at approx 1800 RPMs. Idle and Full throttle and other RPMS perfect. If running just under plane at Approx 1800 RPMs, I hear a slight whine from the engine. Dropping down or over 1800 Rpm it's gone. Any thoughts?? Anything to worry about? EFI Pump noise ?? Harmonics of RPM? Thanks - just trying to be proactive with a new sound ... SteveC

 

[QBhoy]

Fuel pump id think. Wouldn’t worry about it. Lots of technology and clever stuff going on in these great engines.

 

[Texasmark]

Dinged your prop? Running different trim angles? Have a plastic hub insert in your prop rather than a pressed rubber hub? I am noticing that some prop mfgrs are up to revision IV on their hubs to stop rattling.....comments in Props section right on this forum today under Forum first listing: Boat section at the top, sub section Props.

Ask because you said "recently" and it is now and wasn't before. Engine running strong....nothing suspect there. A resonance developed somewhere. You said regularly serviced which would/should include lower unit gear oil replacement.

 

[Canufixit2]

I DID change props - and I'm going back to my old "pre notice whine" prop tomorrow. Lower unit oil was changed in October lay up. And by "recenlty" I meant recently noticed - meaning it may have been there for some time but not noticed by moi. Normally run at min speed cruising or 3/4 throttle to move it along....

 

[Canufixit2]

Hi all, Just Update. Change my prop back to my old prop that did not have the noise. Whine is gone. I'm assuming that an harmonics build up in the affected RPM range was the cause due to prop change.... Thanks All !!!